S-19500A03A-E8T1U4 Datasheet, PDF (6/52 Pages) Seiko Instruments Inc – CMOS VOLTAGE REGULATOR WITH WATCHDOG TIMER AND RESET FUNCTION

FOR AUTOMOTIVE 125°C OPERATION HIGH-WITHSTAND VOLTAGE CMOS VOLTAGE REGULATOR WITH WATCHDOG TIMER AND RESET FUNCTION
S-19500/19501 Series
Rev.1.2_01
 Pin Functions
1. WADJ pin
This is a pin to connect an external resistor in order to adjust watchdog activation threshold current (IO,WDact). Table 6
shows the connection of the WADJ pin depending on the usage of the watchdog timer.
In the S-19500 Series, the watchdog timer is deactivated regardless of the connection of the WADJ pin if the
watchdog timer is set to Disable by the WEN pin.
Table 6
Usage of Watchdog Timer
Connection of WADJ Pin
Watchdog timer is not in use
Connect to the VSS pin
Watchdog timer is always activated
Connect to the VOUT pin via a resistor of 270 kΩ
Watchdog timer turns on and off autonomously
depending on the load current (Autonomous
watchdog operation function^*1)
Open, or connect to the VSS pin via an external resistor^*2
*1. Refer to "3. Watchdog timer block" in " Operation" for details.
*2. Refer to " Selection of Watchdog Activation Threshold Current Adjustment Resistor (RWADJ,ext)" for details.
2. DLY pin
This is a pin to connect an external capacitor in order to adjust the release delay time (trd) of the detector and
monitoring time of the watchdog timer. Refer to " Selection of Delay Time Adjustment Capacitor (CDLY)" for the
selection of an external capacitor.
3. WO / RO pin (S-19500 Series only)
This is an output pin for the detector and the watchdog timer. The output level is AND logic of the detector and the
watchdog timer. (For example, the WO / RO pin is "L" when the WO pin is "L" and the RO pin is "H".)
4. WO pin (S-19501 Series only)
This is an output pin for the watchdog timer. It outputs "H" when the watchdog timer stops or if the DLY pin voltage
(VDLY) exceeds the upper timing threshold voltage (VDU) when the watchdog timer operates. It outputs "L" if VDLY
falls below the lower watchdog timing threshold voltage (VDWL) when the watchdog timer operates.
5. RO pin (S-19501 Series only)
This is an output pin for the detector. It outputs "H" when VDLY exceeds VDU, and outputs "L" when VDLY falls below
the lower reset timing threshold voltage (VDRL).
6. WEN pin (S-19500 Series only)
This is a pin to switch Enable / Disable of the watchdog timer.
The watchdog timer becomes Enable if the input is "H", and becomes Disable when the input is "L". Since the WEN
pin has a built-in pull-down current source, the input becomes "L" when using it in open.
7. WI pin
This is an input pin to recieve a trigger signal from the monitored object by the watchdog timer. By being input a
rising edge at an appropriate timing, the WI pin confirms the normal operation of the monitored object. Refer to
"3. Watchdog timer block" in " Operation".
6